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Guide to Z Ursae Majoris

A reliable variable star located in the 'bowl' of Ursa Major.

Z Ursae Majoris is a red giant star whose brightness variations are due to pulsations in its our layers. Although it is classed as a semi-regular variable, Z UMa can be relied upon to produce a good amount of brightness variation on a regular basis. 

Extreme brightness range 6.3 - 9.8
More typical range 6.9 - 8.7
Period of variation About 6 months (longer secondary period is also present)
Frequency of observation Worth checking a few times per month
Observe using 50mm binoculars will suffice for most of the time, but 60-80mm binoculars may be required during the deeper minima
Visibility Can be observed all year round.  Circumpolar

The following charts show the location of Z Ursae Majoris.

You can follow the brightness changes of Z UMa by comparing its brightness with that of the lettered comparison stars.

The first chart, which is approx 11 degrees x 8 degrees, shows the brighter comparison stars (A to D).

The second chart, which is approx 6 degrees x 4 degrees, shows the fainter comparison stars.